I am designing a home system based on car audio components. I planned to use 12v power supplies to run the amps. I'm curious as to how powerful the power supplies need to be. I'm assuming that they need to have a wattage rating equal to the wattage of the amps, or could they be of lower power?
The power supply needs to be *atleast* as powerful as all the equipment it's running..
Say it's running 2 amplifiers with 20A fuses,and a CD/Radio deck,with a 10A fuse.. Ideally you'd want a supply with atleast 50A capability..but you could probably get by with a bit less,if you don't crank the volume up alot.
Of course,you could always make your own..
Monster MOT supply
Say it's running 2 amplifiers with 20A fuses,and a CD/Radio deck,with a 10A fuse.. Ideally you'd want a supply with atleast 50A capability..but you could probably get by with a bit less,if you don't crank the volume up alot.
Of course,you could always make your own..
Monster MOT supply
msharpe said:OK that makes sense. Well in that case I could use some more advice. What would be the best way to get a power supply(s) with a max power of 2800W?
Your money would be much better spent just buying home amps, it's going to cost you many hundreds of dollars to buy 12v supplies that can feed that much power. If you buy them they're almost $200 just for 40 amps (around 3-400 watts worth, depending on what amp you're using).
edit: I see you posted max power, max power is worthless (especially with these brands out there like Pyle and Dual who slap retarded numbers that have no ties with reality all over their products), what's the rms power you plan to use?
I agree that it would be better to use mains powered equipment.
If you already have the amplifiers, you may be able to find a used switching power supply on eBay. I've seen several 5v/200 amp supplies. You could use 3 in series (each set to 1/3 of the desired output voltage). At 2kw+, you're going to have to power the supply from a 230v outlet.
The following page has a calculator to show you the size supply you'll need for car audio amplifiers.
http://www.bcae1.com/pwrsupdc.htm
If you already have the amplifiers, you may be able to find a used switching power supply on eBay. I've seen several 5v/200 amp supplies. You could use 3 in series (each set to 1/3 of the desired output voltage). At 2kw+, you're going to have to power the supply from a 230v outlet.
The following page has a calculator to show you the size supply you'll need for car audio amplifiers.
http://www.bcae1.com/pwrsupdc.htm
Well, I decided to go with the Ebay route (that's where I was buying everything elsew from anyway ) I managed to snag 2750 watts worth of power supplies for about 80$. This should be way more than enough. The subs are 500watts RMS total for the pair and the other four speakers are "500 watt" 4-way coaxials. Is it a fair estimate to say they are probably about 200watts RMS? I should know for sure when they get shipped to me though. And another question, the subs I bought are by Coustic and the other speakers are by TNT. Are these brands any good? I did buy them for their cheapness I'll admit. And if they are bad, I'll probably try and upgrade to better units later.
I'll probably have some more questions when I start building this beast.
thanks
) I managed to snag 2750 watts worth of power supplies for about 80$. This should be way more than enough. The subs are 500watts RMS total for the pair and the other four speakers are "500 watt" 4-way coaxials. Is it a fair estimate to say they are probably about 200watts RMS? I should know for sure when they get shipped to me though. And another question, the subs I bought are by Coustic and the other speakers are by TNT. Are these brands any good? I did buy them for their cheapness I'll admit. And if they are bad, I'll probably try and upgrade to better units later.I'll probably have some more questions when I start building this beast.
thanks
The power handling of the speakers doesn't matter, how much power will you actually be sending them?
As for the speakers, the "500 watt 4 way coaxials" are probably around 30rms, they fall under the Pyle and Dual category that I was referring to earlier.
And no, Coustic and TNT are not good brands
As for the speakers, the "500 watt 4 way coaxials" are probably around 30rms, they fall under the Pyle and Dual category that I was referring to earlier.
And no, Coustic and TNT are not good brands
It would be a good idea, but not entierly nessesary. Because of the crest factor (peak/avg. power) of music and theather sound, the RMS-value of the suplies can be smaller. Some powersuplies can supply peak values beyond the RMS-value. Others tough don't.
If one has some way of storing energy for times when the power needed peaks beyond what the supply can deliver, one can do with smaller supplies. The key here is battery(ies). They can deliver wast amounts of energy if called upon. The powersuppply/charger only need to supply the effektive RMS value. If one chooses to go with battery(ies), one of course needs to make other choises on what kind of batteries/charger. One other thing one need to take into acount, is that batteries have a more limmited lifespan.
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Dear Sirs,
please excuse me if I jump in this extremely interesting thread with a question maybe a little off-topic.
I have found a huge 2kVA - 12VAC toroid and I would like to use it along with an also huge diodes bridge and suitable smoothing caps.
After the caps the the voltage would be around 17 VDC, if I am not wrong.
In general could it be too high voltage (i.e. 17 VDC) to power a car audio amp ?
I cannot find in the specifications the admissible voltage supply range.
Thank you so much again.
Kind regards,
beppe
italy
please excuse me if I jump in this extremely interesting thread with a question maybe a little off-topic.
I have found a huge 2kVA - 12VAC toroid and I would like to use it along with an also huge diodes bridge and suitable smoothing caps.
After the caps the the voltage would be around 17 VDC, if I am not wrong.
In general could it be too high voltage (i.e. 17 VDC) to power a car audio amp ?
I cannot find in the specifications the admissible voltage supply range.
Thank you so much again.
Kind regards,
beppe
italy
Well, I'm certainly no expert, but I do know that most car amplifiers should be able to handle at least 14.4 volts DC, as this is the fully-charged voltage of a 12 volt car battery. I would image that running one off of 17 volts would present no danger. If anyone else has anything to say on this matter then please do. I'm just making an educated guess here essentially. So, unless someone says that I'm totally wrong, then I would say at least experiment with it.
I've seen equipment (the more expensive ones) than can take 17V but I do think they are the minority. Something tells me 15.6V (or was it 15.2) usually is the highest allowable voltage.
The biggest problem with raising the supply voltage I believe is the supply voltage to the amp section created by the SMPS. It will rise with the same proportion as the +12V line when the SMPS aren't regulated, which often is the case.
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The biggest problem with raising the supply voltage I believe is the supply voltage to the amp section created by the SMPS. It will rise with the same proportion as the +12V line when the SMPS aren't regulated, which often is the case.
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msharpe said:
Dear Sir,
thank you so much for your very kind and extremely valuable reply.
Actually after having read of the high quality of some car audio and also of their ability to source good amount of current to drive demanding loads I had this idea.
Presently I am learning and gathering technical info.
Another datum that I have to establish is the needed amount of capacitance after the diodes bridge.
After that I can start testing some nice car audio amps I can obtain from friends.
Thank you so much again for your very precious advice.
Kind regards,
beppe
Why not disconnect the SMPS in the amp and run a 120V (240v) to whatever your rails are transformer (to the rectifier)? This would skip a couple conversion steps that you are needlessly making using 12V supplies.
Here is what you are planning to do:
120vac - transformed - rectified - filtered to 12-14Vdc - SMPS back to AC (square wave) - transformed to Rail voltage - rectified filtered.
Using a Mains toroid its:
120vac - transformed - rectified - filtered to rail voltage.
To step voltage up or down you need to have AC, you are starting with AC, no need to convert it to DC and back.
It would be easiest with an unregulated PS car amp.
-Ken
Here is what you are planning to do:
120vac - transformed - rectified - filtered to 12-14Vdc - SMPS back to AC (square wave) - transformed to Rail voltage - rectified filtered.
Using a Mains toroid its:
120vac - transformed - rectified - filtered to rail voltage.
To step voltage up or down you need to have AC, you are starting with AC, no need to convert it to DC and back.
It would be easiest with an unregulated PS car amp.
-Ken
Vodkatonics said:
That is a good idea in some ways but in others for example the protection circuit of the amp will be usless.
Most amps protect them selfs (and speakers) by turning off the psu. If you power it from mains with out building into the protection part, any problem that arrises will or can destory the amp or speakers.
The SMPS solution made real:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=60969
This project is on hold, as I'm currently working on other stuff, but I would still like to finish that power supply and turn it into a nice commercial product in the future. It will include a "stacking" feature to obtain up to 1000A through active paralleling techniques. I might even get it distributed in USA if there is enough demand.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=60969
This project is on hold, as I'm currently working on other stuff, but I would still like to finish that power supply and turn it into a nice commercial product in the future. It will include a "stacking" feature to obtain up to 1000A through active paralleling techniques. I might even get it distributed in USA if there is enough demand.
I powered a car amp from the mains,with a regular transformer once while I was waiting for the SMPS FET's to come in..I actually left it that way for a few months running my subwoofer,but eventually replaced the SMPS FET's,and then built a 12Vdc supply with a microwave oven transformer to test the complete amp.
Easy to experiment with different power supplies and stuff too..
(with a 50/60hz mains transformer,you'll need to add more filtering than stock.)
BUT-Do beware that when bypassing the internal SMPS most/all of the protection circuitry will be disabled! (already mentioned,but a good point to repeat!) Don't wanna fry any amps/speakers.
Easy to experiment with different power supplies and stuff too..
(with a 50/60hz mains transformer,you'll need to add more filtering than stock.)
BUT-Do beware that when bypassing the internal SMPS most/all of the protection circuitry will be disabled! (already mentioned,but a good point to repeat!) Don't wanna fry any amps/speakers.
Piece of cake.. Connect the protect ckt to a relay or SSR that supplies the mains. I use Sharp solid state relays in a lot of pic designs. They have 4 pin SIP and smd packages that can handle 16A at 480V with a 5V or 1.2V input for less than $5.
I will admit, that it would be more "work" to connect the amp to mains via a transformer. It would require some skill too. However, it would be the most efficient and least "clunky". My 30A 13.8V supply at the shop is the size of 2 shoeboxes and thats a small power supply. A 100A regulated supply is bigger than an ATX size computer. Conversely a 1.5KVA Toroid transformer is the size of a large coconut.
On the cheap and easy but VERY clunky.. A car battery charger and battery is probably the lowest cost solution. A Battery charger is horribly dirty but so is an alternator (3-phase ripple DC).
-Ken
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